Scientists Seek Scent of Life in Methane at Mars

Sniffing out any whiff of biology on Mars has become a scientific battle of the bands � spectral bands that is.

The purported detection of methane in the martian atmosphere by Mars Express, the European Space Agency (ESA) probe now orbiting the red planet, has sparked measurable debate.

ESA announced late last March that the Mars Express Planetary Fourier Spectrometer (PFS) had observed methane. That instrument is built to detect the presence of particular molecules by analyzing their 'spectral fingerprints' - the specific way each molecule absorbs the sunlight it receives.